My Windows PC uses an older Fenvi 1200-style Wi‑Fi card that I bought several years ago. Recently, the connection has started dropping, and the adapter disappears from the available network list for a few seconds before returning. Sometimes the signal indicator falls to one or two bars, which mainly causes instability and high ping rather than noticeably slower downloads. The problem happens more often on 5 GHz than 2.4 GHz. The router is about 20–25 feet away, and nothing significant has changed in the setup, so I'm unsure whether this is caused by interference, a bad driver, or a failing Wi‑Fi card.
2 Answers
The 5 GHz band has less range and penetrates walls worse than 2.4 GHz, so it can be more sensitive to interference or a weakening adapter. Check which channels nearby networks are using, and try a less crowded channel. Avoid increasing channel width while troubleshooting because wider channels can create more overlap. Also reinstall or update the adapter driver, test with 2.4 GHz, and see whether the adapter still disappears from Windows entirely. If it does, that points more toward the card, its power management, or the USB/PCIe connection than simple signal strength.
Since the adapter vanishes from the network list instead of merely slowing down, I’d first check Device Manager and disable any setting that lets Windows turn off the Wi‑Fi device to save power. Then install a fresh driver from the adapter or chipset manufacturer, rather than relying only on Windows Update. If the problem continues on both bands, try reseating the card and its antennas. Given its age and the recent instability, replacing it with a better-supported adapter may ultimately be the simplest fix.

There are only a few people in my building, and the router is fairly close. The issue only started recently even though the setup has been unchanged, so I’m leaning toward the driver or the card failing.