Computer help: memory also low

memory also low

my computer Dell I1720 Intel Core 2 Duo T7250 @2.0 Ghz w/ 2GB Mem. with a 250GB Hard drive.My system seems a little sluggish i have a program called Advanced SystemCare Ver 3.3.4 Pro,this program does everything,and i mean everything.Its probably the only tool or program i pay a fee for.It will go over my system and correct almost everything,that i can think of,it always seems to get me out of a jam.And always seem to return my computer to a state that operated well.Well now it seems no matter what i do with it,my computer seems a little sluggish.What happens is weird to me,if i start my wireless ATT card sometimes i have to hit CNTRL+ALT+DLT button and make it seem as though i want to open the task manager and then the program starts working,and i dont even need to use it,this happens a few other times to and then i assume im okay from there.Any opinions about what is causing this.