Upgraded RAM and Reinstalling Windows

[EM1958]

I have two computers that I bought in 2004 brand new, one that is a Dell that died 6 months ago, and one that is an HP Pavilion a475c that is still running, but very slow. I recently upgraded the RAM to 2 GB and added an external memory of 1TB and moved as many folders and files as it would let me to the ext. memory. It is STILL running very slow and hangs up alot. Your site suggestions mentioned possibly uninstalling and reinstalling Windows XP. I had XP Home Edition on both computers, but I do not have my original installation disk for Win XP for the HP, but I do have a reinstallation disk for Win XP for the Dell (but it says on the pkg that it is to be used only with my Dell...?) I have my original Product Key for Win XP on a sticker on the side of the HP. Can I use the Win XP reinstallation disk from the Dell to reinstall it on my HP using the original product key?

Also, since the RAM upgrade, sometimes it hangs up when rebooting and emits a very fast beeping sound (no pattern, just continuous). I have to reboot to get past it. Why? And how do I fix this?

Thanks for any help you can offer on either of these....EM

 

[EM1958]

Sorry, when I submitted this post, I got an error message saying it couldn't post, so I reposted again. Evidently, it DID go through the first time. Sorry for the double post! ---EM

 

[Hawkeye22]

Those are OEM install disks and will not work in the other computer. If your HP has a recovery partition, you can just boot to it and restore the PC to factory. Of course you will want to back up all your data first. you should see something when you first boot up, like F11 - Recovery