@danielwils47364 nice phone. first you will have to make sure that your phone has a SIM card that it does understand. Some of these "older " phones required you to have a carrier SIM card to start. Let's see if it is locked to a provider.
Check [https://www.hardreset.info/devices/sony-ericsson/sony-ericsson-w995/faq/faq/unlock-network-locked-sim-card/|this site] to see if your phone is network locked
Next you can check to see if it can be unlocked.
1. Turn on the phone without sim card
2. Type *#*#7378423#*#*
3. Select Service info
4. Select SimLock
5. Check where the X is 6. If X is on NETWORK, SUBSET or PROVIDER and value is more than 0, you can unlock your phone.
7. If it is 0 unlock by code is NOT possible. The counter is blocked.
Not sure if anybody even still support unlock codes :-) but it at least should give you an idea.
Apparently there is an unlock menu that you could try. Check [https://www.youtube.com/watch?v=N-NC40CPKsA|this video] as well as the comments.
This "but it asks for a sim. When I place a sim card in, it gives an error of "Incorrect sim card" means that your SIM card reader knows that there is a SIM inserted. That would imply that the reader still works. Here is a document that might be of use to you [document|33101] PAge 21 could be of interest
Now, if you do have the proper SIM card etc for this phone and it still gives you this issue, you could consider replacing the SIM card reader.