Reinstalling any program frequently results in losing patches that may be significant, so it's a good practice to check for updates after a reinstall.

Very rarely it may be a new patch that causes a problem, but if all but one site works, that's even less likely. (Some, but not all, patches can be "backed out" individually, so reinstalling the program may not be necessary if a patch breaks something for you.)

Release of a new patch sometimes reveals a vulnerability that the "casual hackers" didn't know about, so there's often a flurry of attacks on a vulnerability that's just been patched, to catch those who don't patch promptly before they get protected.

Although there hasn't been much "officially reported" there also seems to have been a recent surge in DDOS attacks, mostly on DNS Servers, that have no discernible purpose and no visibly organized intent. They may be only because reported organized DNS Server attacks made some of the "less serious" hackers aware it could be done. These attacks have been rather "random" since many of the attacked DNS servers only affect small areas or small groups of users.

John