I'm assuming that you have some form of antivirus software and a firewall. If not, you should get them. There are free versions of both, or you can spend $20 a year and get
ZoneAlarm Antivirus , which has a free trial period. I've used that myself for two years.
You might also want to download the free version of
AdAware and also
Spybot Search and Destroy .
It doesn't hurt to clear your temporary internet files (cache) In MS Internet Explorer (browser), that's found under: Tools/Internet Options/General tab/Delete Files.
And as suggested, you can uninstall all of the poker and casino software that you don't want.
When done, you should use Disk Defragmentor, which you can find under Start/Accessories/System Tools/Disk Defragmentor.