Slow system

I posted this in the wrong forum this morning, oops. Here is my problem. The machine I use starts slow and programs open and responds slow, I have read and completed the steps in the basic spyware and trojan, virus removal and found a few items that were removed. I have a feeling that I am asking too much out of an older system, I run Photoshop 7, ACAD 04, Illustrator 9, they are the big ones along with the typical office products. I also use Firefox as well as Thunderbird. Any help is appreciated I thank you in advance. My system specs are as follows:

Win XP Pro sp2(build 2600)
2.0 gig P4
8 kilobite primary memory cache
40 gig hard drive with 31 gig free space
Bus clock 100 mhz
256 MB memory

 

Thanks for the info, I will run that and post.