CA1C and TDBICXL doesn't show up in Google, but STUC.IDX came up with a couple of hits, but no real idea of what it was, although the problem seemed to be the same, ie there were a lot of these files that suddenly appeared.
IDX files themselves when Googled came up with a lot of different hits, and I know that Incredimail uses such file extensions. But nothing I could see that matched your problem.
Suggestion. Take out the IDX files and store them somewhere else on your C drive, eg a new folder that you can easily remember.
See if you have any problems with WMP. If so, return them to where you found them and see if that solves the problem.
If you have no problems, then you can perhaps delete them after a week or so.
At the same time, I would suggest you do a complete anti-virus, anti-spyware and anti-adware sweep of your system, and make sure your firewall is on.
I have Windows XP Professional 2002, Compuserve, AMD Duron (tm) Processor 847 MHz, 504 of Ram. My questions is this: I use Windows Media Player and have my music stored in "my music" file. I have dozens of IDX Files starting with CA1C up to and including STUC.IDX and TDBICXL. I never had these before that I recall and want to know if they are necessary for correct song format and use of "my music" or can I delete them. Thanks for any help you can give me.