If you have recently reformatted your hard drive, then you probably lost your drivers to your web cam. Regardless you should check to see if you have them.
Go to the control panel, then to hardware and sound, then to the device manager(I believe this is where it is located on XP, but I'm not sure). In the device manager, check under something called imaging devices(this is usually what it is called). Now go to the drivers tab and check to see if it has any drivers. If it doesn't then update them, either by clicking update and let windows handle it or go to the manufacturers web site.
If you didn't see anything, then look under any called unknown or other devices. If you find anything that sounds like it could be your web cam, then you need to update them. Read the previous paragraph to find out how.
I hope this solves your problem.
As far as recording videos...
Your web cam should be able to record videos(I'm assuming since my web cam can record videos). You may need to install the program to use that feature though. If you don't have the any installation disks for it, then check the manufacturers web site for any kind of update.
But on a side note... I wouldn't use a web cam to record any kind of video(unless you have a very good web cam). Video is usually low quality, not to mention audio on something like that probably wouldn't sound very good.