i had somewhat similar problem. first of all make sure that there are no programs running in the background. Also get a regcleaner
http://www.vtoy.fi/jv16/shtml/regcleaner.shtml and clean the registry. another thing use your computers feature to search for "msconfig". then go to startup tab and uncheck as many apps as you can. If all else fails as it did in my case format your hard drive and everything should run as great.