I've solved the problem by following procedure:
My router configuration
Authentification mode: Shared key
WEP Encryption: WEP-64bits
Key index 1
Initially W7 won't connect to the wireless network.
My steps
I have Czech version of Windows 7, so, please note that text in English version might be slightly different from my translations.
- Goto network and sharing center
- Select Setup new connection or network
- Select Manually connect to wireless network
- Type network name, select WEp security and enter key, finally click Next
- Click Change connection settings
- Goto protection tab
- Select Security kind: Shared and Encryption kind: WEP
- Retype network key
- Precc OK and Close
This worked for me.
In case you already have some setup for your SSID, delete id before.
Đ.