Regarding the first specific problem mentioned:

If I plug the headphones in, the speaker outlet stops working

Hint: that's what it's supposed to do on most newer computers. That's not really a Vista thing. Modern up-to-date and "withit" manufacturers understand that the only use of headphones is so tweenyboppers can listen to gangsta rap without their parents hearing it. When you plug in the headphones, the speakers are silenced so you can blow your own ears out without disturbing everyone else.

It's quite likely that the headphone jack includes a switch to turn off all other sound outputs when you shove a plug into it.

Vista claims to have better capabilities for running older software than previous Windows versions, and it's possible that there's some truth to the claim; but lots of older programs use "insecure" methods, and Vista doesn't - by default - allow them to do what they need to do, unless you change security settings to specifically allow the "unsafe" methods. The problem here is that Microsoft has provided absolutely no useful help on how to set up the security permissions to do this.

If there really is a problem with "obsolete software," Vista should tell you about it. The typical first symptom is a popup that tells you that there's a problem with the software, usually allowing you to choose to "run anyway." This is typically followed at the next boot by a message informing you that the program has been disabled. The only general criterion for Vista rejection of an older program that I've found is that any program that accesses an optical drive without automatically contacting the "Copyright Police" to tell them what's on the disk will be disabled. (DRM policies are quite rigid in Vista, apparently.)

There may be other reasons for failure to run, but mostly these will be associated with "illegal" - per Vista standards - processor or hard drive access methods and/or programs with known serious and unpatched malware vulnerabilities. If Vista doesn't tell you it's a "bad program," then the program should run, although - as noted - you may have to set up specific security policies to allow it to run properly. (But don't ask how that's done.)

One of the major problems Microsoft has admitted is that they did not provide sufficient "advertising" of new Vista characteristics before putting it on the market. This has been solved by putting nothing but advertising on Microsoft support sites. At least for the present, there is nothing useful there.

Persons attempting to use Vista - and the new Office Programs - must accept the mandatory requirement that an entirely new language must be learned. It is uncertain whether this language is an archaic form of "Mac Speak" (current Macs aren't as obtuse) or is just "baby talk." The high-level former Apple administrator that Microsoft hired under a title carefully crafted to conceal any association with Vista, quite probably left Apple because of an argument over whether the primitive descriptive language he favored was being dropped in favor of having at least a few terms intelligible to persons other than "creative artists" and/or "magazine editors." There is at least an obvious evidence in what I've been able to translate indicating that only a few sub-teens and perhaps selected chimpanzees will find the new "Vista-speak" a "natural" method of communication. That executive has recently submitted his resignation from Microsoft "to seek new opportunities."

Example:

The instruction "To open a file, click "File" and then click "Open."

Is replaced by:

"To perform a task that involves using a document or other object that exists on your computer, click the

            COWSPLAT

at the top left of the window that you have open. There you will find several choices for tasks you can perform if you choose to do so."

When you click the

            COWSPLAT

you do not find a place to simply click "Open a file." Instead, you find a multitude of helpful(?) instructions like:

"If you would like to perform a task that involves using multimedia connections please provide your complete name, address, email address, social security number, bank account number, credit card number and expiration dates, and you mother-in-law's maiden name and you will be instantly connected to someone who will provide you with thrilling and current multimedia programming and content for your immediate purchase and enjoyment."

Approximately a dozen additional and very similar choices may be offered.

At the next click (random selection is about as effective as trying to follow the instructions) you may encounter:

"If this choice did not provide the proper task management utilities to do what you want it is because YOU ARE AN IDIOT. You should not take offense at our providing this information, but be assured that you are exactly the kind of person this system was designed to please, and the features incorporated here are entirely for your amusement and enjoyment."

Okay - so maybe I overstated things a bit(?) - or maybe not. It's only because I just don't yet understand the new Vista-speak.

If your seller's support people can't fix your problem, it is entirely possible that they're a bunch of rip-off artists who have no intention of supporting what they sell; but it's also possible that their support staff consists of people over the age of 13 who don't yet speak "Vista" - or their chimpanzee is busy helping others. Good luck finding someone who does speak the language.

John