[exaltedwombat]

You don't need to keep restarting the ol numbering. "Start" isn't supported in EPUB2 anyway. Neither are some other items you've used, the code won't pass validation.

If you wish the table to fill only half the page width, correct the misprint "sytle" in line 1. But I suspect you don't need that bit at all.

Here's a start. But run Validate in Sigil and see where your other problems lie. There are easier ways to place a border round a paragraph.

BTW I think there are laws against advertising quack cures for cancer.

<table class="center" border="1" sytle="width:50%">
      <thead>
        <tr>
          <th>SPECIFIC WARNING SIGNS FOR COMMON CANCERS</th>
        </tr>
      </thead>

      <tbody>
        <tr>
          <td>
            <ol>
              <li>COLONORRECTAL CANCER: rectal bleeding, blood in the stools, and change in bowel habits.</li>
            
              <li>
                <p style="text-align: justify;">BLADDER CANCER: blood in the urine and increased urinary frequency.</p>
              </li>
            
              <li>
                <p style="text-align: center;">SKIN CANCER AND MELANOMA: a change in the color or size of a mole, generally involving the spread of pigmentation, oozing, bleeding, scaliness, tenderness, and itchiness.</p>
              </li>
            
              <li>
                <p style="text-align: center;">PROSTATE CANCER: Weak or interrupted urine flow, blood in the urine, and nagging pain in the lower back, pelvis, and groin.</p>
              </li>
           
              <li>
                <p style="text-align: center;">BREAST CANCER: a lump, swelling or thickening in the breast, or other changes in the texture of breast tissue; nipple discharge or retraction; and dimpling of the skin.</p>
              </li>
            </ol>

            <ol start="6">
              <li>
                <p style="text-align: center;">CANCER OF THE PANCREAS: despite no specific early warning signs, there is often regular abdominal pain and digestive difficulties as the cancer progresses.</p>
              </li>
         
              <li>
                <p style="text-align: center;">LUNG CANCER: nagging cough, chest pain, streaks of blood in the sputum, and recurring pneumonia or bronchitis.</p>
              </li>

              <li>
                <p style="text-align: center;">LEUKEMIA / LYMPHOMA: fatigue, weight loss, paleness, persistent infections, swollen lymph nodes, easy bruising, fever and night sweats.</p>
              </li>
         
              <li>
                <p style="text-align: center;">CANCER OF THE UTERUS OR CERVIX: bleeding in the vagina unrelated to menstruation and an abnormal vaginal discharge.</p>
              </li>
            </ol>
          </td>
        </tr>

        <tr>
          <td valign="top" width="357">
            <p align="justify" style="text-align: center;">10. The good news is that while cancer cannot be cured by conventional medicine (surgery, radiation, chemotherapy), alternative natural medicine has repeated shown that it can be cured — especially by therapies that involve chiefly uncooked foods and raw vegetable juices like carrots, beets, celery, etc. The truth is often stranger than fiction. Believe it or not!</p>
          </td>
        </tr>
      </tbody>
    </table>