What is the model number of your laptop?
What OS is installed on the laptop? Have you got the latest WiFi network adapter drivers appropriate to your laptop and OS installed?
Does the WiFi work OK when you are very close, (I mean very close) to the router? If so perhaps there is a loose WiFi antenna connection in the laptop
Download, install and run a WiFi scanner program on your laptop (this one is free, there are others if you prefer, just search online for WiFi scanner program). Use it to check the WiFi signal level, received by your laptop. Remember that the signal level is in -ve values, therefore the higher the number the lower the signal strength, e.g. -100dBm is weaker than -93dBm.
If you are receiving low level signals then perhaps the antenna connection to the WiFi is loose.
Also another way to improve WiFi (although perhaps not in your case as other devices are OK) is to check which 'channel' your network is using. By default most networks use Channels 1, 6 or 11. If you find that the scanner detects other networks using the same channel as yours and their signal is relatively strong in comparison to yours then change the channel in the router to a 'quieter' one (one that doesn't appear in the scanner list of channels or has minimal appearances ) to minimize any possible degradation to your network through interference.