Slow start-up and performance

[M-A-G]

My laptop's been in my possession since February of this year and it has been one of the best investments until about maybe 3 or 4 days ago. I noticed that it was starting to take a considerable amount of time (almost 5 minutes) to load up from the second I turn on the power to the moment my Explorer is ready to go. Also I began noticing that when I try opening a program, the CPU devotes almost 100% of its power into opening it thus depriving any other programs from functioning smoothly. I first noticed it when playing music while playing EWR. The music would stutter horribly and skip much like the start-up and sign off jingles. I've checked everything that I'm familiar with when it comes to memory management but I've barely risen above the memory usage that's already in place by the proper Windows files and defragging and disk clean-ups and system restores don't seem to help. Is there something I'm missing? Are there excess background programs I can stop using the Task Manager? And if that's the case, what's the explanation for the slow start-up and shut down? Please help. I'm fearing I'll have to replace this laptop quicker than the old one or do a complete system recovery.