Install the system first and then partition the x300 without the optical drive. Install the win7 C drive partition.

I recommend a lossless partition tool under win7.Acronis Disk Director Suite

Acronis Disk Director Suite
Http://dl.iplaysoft.com/files/32.html

Acronis Disk Director Suite registration Machine
Registry.rar

Don't worry, if you think the registration machine is toxic, you can use the following serial number
LS6ZZ-YFQYY-667Z9-5ZQGP-P7WCP
5prkn-9r46t-hgyn6-86v5d-9u3vf
XMYP4-QZBQ6-7TUHY-HR5NQ-GUVPC
7vfjp-k9249-g9k9y-c2pgk-7vl53
EWRCT-AGVS8-3CRU2-FXPNP-M9M53
KDJ4A-CC29D-MK3XV-RYYWA-VCPXE

Acronis Disk Director Suite lossless partitioning tool tutorial

1. Select to create a new partition (the first option in the left sidebar)

2. Select Hard Disk

3. Select a partition

4. Adjust the capacity of the new partition

5. Select the partition type (either primary partition or logical partition)

6. Select the partition file format (usually NTFs)

7. Allocate drive letters

8. Volume name (optional)

9. Check the partition structure.

10. Select the flag.

11. Select proceed. (If you want to adjust the partition of the primary partition, you must restart the primary partition)

After the reboot, your hard disk now has two partitions, and the c disk has no loss.