Hi OptimisticSimplicity, This could be because of a security update; the DNS (Domain Name System) settings may be corrupted. As the system was able to connect to the internet 4 days ago, you can try to run a ‘System restore’ to a known good date when the internet was last working and then perform the Windows update and the MacAfee update. Please use the link below, which explains how to perform a system restore in Windows 7. [URL] For your information, System restore will not delete any personal data; however it will delete any programs, windows updates or any other updates that took place recently. For example, if you are selecting the restore point to be the 15th of August, any programs installed to date after the 15th will be removed. [URL] I hope this helps. Please do write back in case you need any further assistance on the same. Thanks & Regards Swapnajan MC #iworkfordell
I bought Dell Inspiron 5520 two weeks ago in Dubai, UAE.   My Internet was working fine first couple of days but since past 4 days I am not able to connect to internet via Wifi (however there are other laptops i.e. HP and Dell) that are able to use the same Wifi to connect to internet but my brand new Dell us not able.   Can anyone please help me? I am not quite techie, only understand very basics of this whole laptop (hardware and softwares etc)   I have Windows 7 and McAfee pre-installed. 
Dell Inspiron 5520 laptop unable to connect to internet via Wifi