I would go down the hardware path rather than the software one.
what are your current wireless components, the modem/router and the adapter in your PC?
what are the ages? if old, wifi technology has improved a lot recently (in terms of speeds, coverage and penetration)
also, if the modem/router is a few years old, it may be flaky.
all in all, a new modem/router and/or a new wifi card in the PC would be the best place to start.
another consideration, try connection the PC to the modem/router via an ethernet cable (bypassing the wifi connection) and see if that helps.
also, what is your internet speeds?
there are many 'speed test' sites, but I like this one; speedof.me (exactly as written, no www.)