Wireless driver disappareared

Hello,
the othe day i wanted to install a router when I learned that I do not have a wireless driver on my DELL Inspiron 600. This was a big surprise as I used the for three years running before. This laptop is about 5 years old. Can on eplease help me as to hat driver U need to download and how to fix the problem?
I am in healthcare and it would be very impurtant to have a wireless connection. I live in Europe if that makes a difference. Thanks in advance fo the help or advice!























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