Some things to look at are:
1) Consider updating your video drivers. This would require downloading latest video drivers from manufacture.
2) You might benefit from upgrade of DirectX.
3) Maybe during the install some programs where put into the background. You can check your msconfig to see what is running at startup.
Start/Run/msconfig.
These can be places to look.
And as always run ad-aware, spybot search and destroy and a good virus program.
