|"Since you had to replace the HDD, you had to reinstall XP, right? Did you install all the latest drivers & Windows Updates? "|
That has the most effect on the performance of your system. If you haven't loaded the drivers for your particular mboard, your system will probably run a lot slower than it is capable of.
XP doesn't have the drivers built in for most things that first came out after XP was first released, circa 2001, and it doesn't have some of the drivers built in for things made before that.
Whenever you load Windows from a regular Windows CD (or DVD) from scratch, after Setup is finished you must load the drivers for the mboard, particularly the main chipset drivers, in order for Windows to have the proper drivers for and information about your mboard hardware, including it's AGP or PCI-E, ACPI, USB 2.0 if it has it, and hard drive controller support. If you have a generic system and have the CD that came with the mboard, all the necessary drivers are on it. If you load drivers from the web, brand name system builders and mboard makers often DO NOT have the main chipset drivers listed in the downloads for your model - in that case you must go to the maker of the main chipset's web site, get the drivers, and load them.
Load the main chipset drivers first.
If your XP CD does not have SP3 updates included, the best time to load them is right after you have installed Windows from scratch, before you have loaded a lot of other software, because you're unlikely to have any problems while installing the SP3 updates, or any problems after they have been installed, in that case.
Don't install anti-malware software before you install the SP3 updates, especially Norton / Symantec products.
It's perfectly safe to access the web before you have anti-malware software installed, for the site for your mboard manufacturer's or brand name system's web site, and the major main chipset maker's web sites, so that you can get drivers, and to access the Microsoft Update page on the Microsoft site to have it Express search for the updates manually - however, don't randomly search for anything on the web until you HAVE installed anti-malware software .
If your CD has SP2 updates included, you only have to install a few things there at the Microsoft Updates page, then the only thing listed is the SP3 updates.
If your CD has SP1 updates included, or no SP updates included, you have to install more things there, and possibly have to go there several times, THEN the only thing listed is the SP3 updates.
After the SP3 updates have been installed, you can have it Express search for more updates there, or just let Automatic Update do that that gradually..