What's wrong with my laptop?

last week laptop was dropped from my hand and problem was start. So hard drive crashed so I replaced and it has worked OK since. Now sometimes it freezes for a few minutes and eventually it catches up and makes essentially every click that I had when it was frozen. I replace the RAM (because when i opened the RAM has been set up and not stick to flat).

I replaced the 2 sticks of 512 MB RAM 2 - 1 GB of RAM sticks, and it seems much faster, but since I put new RAM in the gel, it was like crazy (bad open IE, and it hangs for 5 minutes, ill close IE and open something else and it freezes again.).

I don't know whats the issue can you help me ?

Thanks

I think your motherboard was damaged.
Are you 100% sure that you have purchased the correct RAM?
Look in Event Viewer for errors. Start, Run, Eventvwr.msc

I am 100% sure it is the correct RAM, I found the part # online and search this way and that the computer recognizes the RAM . There is difference in capabilities between multi-tasking having now 1 GB and 2 GB of RAM.

Then set the virtual memory system or to configure anything. Many people to improve memory and does not change the virtual memory settings to match.

Panel, system properties, advanced, performance settings, virtual memory, change, decide to leave the windows.