PureText - I use this daily - it lets you paste the plain, unformatted text of the clipboard - http://www.stevemiller.net/puretext/
A windows clipboard tool. Open source. Captures multiple items - http://ditto-cp.sourceforge.net/
Windows XP clipboard can be locked by a program or corrupted. Was able to clear using "delete" in clipbrd.exe (system32 folder... already in path)
tags: clipboard, windows, clip, copy, paste