So I had some dust stuck in the intake vent and I opened the laptop for its first good cleanup in 9 years. I got carried away and opened the whole thing up(removed the hard drive, RAM sticks) just to have a look. After getting bored I closed it up and tried to boot it up. The first time I did this the laptop beeped non stop for a whole minute while displaying a black screen with a blinking cursor. It shut up after a while and then probably restarted, after which it was running windows without any hiccups. The problem is after this, it now always takes a long time to start, being stuck on the black screen, then on the windows logo, then finally windows starts up. After about one month with this, the laptop takes consistently 3 minutes to start up, prior to this it was less than a minute. What could be the issue here?