There’s a chance you may lose internet service on Monday unless you check your computer for malware that may have corrupted your machine over a year ago.

More than 250,000 computers worldwide are expected to be effected. The FBI believes around 64,000 are in the United States.

If you lose your ability to use the net on Monday, you’ll have to call your service provider for help deleting the corruption and reconnecting to the internet.

Many internet providers are ready for the problem and have plans together to help customers.