Go online and do a driver search for the WIFI device on your laptop. Just input the model of your laptop and then go look for the specific WIFI driver for it...
The more storage you have the faster that makes your PC functionality because the drive assigned to your operating system is not full and has lot of storage space available...
Have you tried checking for any bad sectors on the hard disk that you have. If not then please check it maybe its the one causing you problems or you can also do full disk scan to search for viruses that may have caused the problem...