If you can find the "Unicode" code number for a character, you can insert the character into Word using the Alt-NumPad method.
Note however that the character can only be displayed in a font that contains that character.
NumLock must be turned on. You must use the NumPad (the numbered keys at the right of the keyboard) On a laptop, the NumPad is embedded in the main keyboard, and must be toggled on for the entry.
Hold down the Alt key while you type the decimal character number on the NumPad, and the character should appear in Word. You sometimes get a different result if the character number starts with a zero (0) than when the 0 is omitted, so try both ways if the first one doesn't work.
In recent versions of Word, you can type the Unicode HEX character number directly into the document, and before you type anything else, hold down Alt and type X. Formally, the Unicode Hex character number should have a U on the front of it, but Word doesn't require it. The preceding Hex number will convert to display the Unicode character - if it exists in the font you have set.
Since most Unicode character charts give the Hex version of the number, this will be much more convenient if your version of Word supports it.
In some cases using the Alt-X conversion, Word can recognize that a "special font" is required and will look for a font that contains the character, but this isn't particularly reliable.
Since Wingdings are a pictographic font that doesn't behave well, if your computer has Lucida Sans Unicode you can use it to get the circle-p character by selecting that font at the insertion point and typing 2117 followed immediately by Alt-X.
Lucida Sans Unicode is included with WinXP/OfficeXP and was available as a free download from Microsoft for other Office users. Rumor says the free download is no longer offered but I haven't checked to confirm that. You may be able to find it elsewhere on the web. Note that versions of Lucida Sans that don't include the "Unicode" in the name probably won't include this character.
Note also that Win98 and older versions have extremely limited ability to use Unicode characters due to the bit-length setup.