I keep having problems with running any Microsoft software on my computer. A program will start up with no problem but will only run for a couple of minutes and completely get out of the program. It seems any of my software that came with Windows XP and Microsoft software loaded later has this problem. I also most of the time cannot turn off the computer properly without it locking up. Do I have a virus or is there something else that could be causing this? I do have Bit Defender as antivirus protection.

Would try ccleaner, it's a registry cleaner/optimizer to see if it could be an issue with some corrupt registry settings

ccleaner (Freeware)
Download CCleaner 2.17.853 - FileHippo.com (http://www.filehippo.com/download_ccleaner/)
On the right hand side, click download latest version

Hope this helps out