Why does my Dell laptop hang up during booting up? Then works on the second attempt?

When I first start my Dell inspiron E1505 laptop 80% of the time it hangs up and will not completely finish the boot up process. I get the desktop but can't do anything or start any programs. Then I restart it and about 95% of the the time that works and it runs fine.Whats up with that?|||the best way to help increase boot speed is to keep your desktop limited to only stuff you need not files or anything like that free your desktop up another thing to do is to run a disk cleanup and defrag every otehr month you can do this by going to start menu applications and system tools. also you can increase your ram.