I've done all the basic checks, virus scanning, disc space, back ground processes and there seems nothing out of the ordinary. My browser has at least 5 second response delay minimum and just everything I click my pc will just crash or take forever to load. Specs: Windows XP - 64bit Processor: Intel Core, 2quad CPU RAM: 8GB HDD: Hitachi HD ATA
Problem may with your registry or the file system. Try to clean your registry and then defragment it. Your file system may also get fragmented. So defragment your hard drive.
Other important things are :
Make sure you've got the latest drivers for your computer. Especially the latest video drivers. Having out-of-date drivers can cause an assortment of issues.
Make sure your computer and processor is not overheating, excessive heat can cause a significant decrease in computer performance some processors will even lower the speed of the processor automatically to help compensate for the heat related issues.
One possible cause of the hard disk slow down is the PIO mode enable instead of DMA mode:
Check this MSKB article IDE ATA and ATAPI disks use PIO mode after multiple time-out or CRC errors occur
A link for an Hotfix is available from this page
More info about DMA/PIO there: DMA reverts to PIO
Check CPU usage
Use Task Manager (Ctrl+Shift+Esc), select the Processes tab and click the CPU column header to sort processes by descending CPU usage. If there is a process (other than "idle") that is using most of your CPU, most of the time, you can stop that process or prevent it from loading at startup.
In some cases, anti-virus products can conflict with other software. Microsoft's Security Essentials occasional does so (look for "msmpeng" in task manager). You may be able to observe this using Task Manager. If so you can try temporarily disabling other startup processes one at a time and rebooting until the conflicting program becomes obvious.
Use the Start icon to run or search for "msconfig", this lists startup items and allows you to disable them. This can be useful for identifying programs that cause problems.
Backup your data, check you can read all your backups, reinstall Windows, restore data.