What do you think is the best program for my PC as it is very slow

My first recommendation would be to make sure you have antivirus, antispyware, and firewall. The antivirus and antispyware should have scheduled scanning and real-time monitoring, and everything should be kept up to date (if they don't update automatically). My next recommendation is Process Tamer, which automatically lowers the priority of "narcissistic" processes that think they need the whole CPU to themselves when performing a single task. Another goodie you might look into is Advanced Windows Care. There is a free version, which does a decent job of optimizing your machine for you. Finally, I recommend you defragment your hard drive at least once a month. You can use Windows Disk Defragmenter, or find another one on the web. Diskeeper is one of the best that is offered in a free version. Hope this helps!