Start simple

When my wifi starts to slow down, I first unplug the modem then the router, wait about 30 seconds, then plug them both back in--usually just a simple reboot will do it. If not, then disable the wireless connection on your laptop, restart it, then find your wireless network and re-connect. If this still doesn't do the trick, then start with any of the other suggestions posted (getting rid of the bloat-ware first--that can really slow everything down). Hope by now you've got a stronger signal!